JPH0252825B2 - - Google Patents

Abstract

A process and apparatus for measuring the degree of pollution, the degradableness, and the level of toxicity of aqueous liquids such as effluent. A partial stream is withdrawn from the liquid undergoing examination and diluted with biologically neutral water. The diluted partial stream is oxygenated and continuously flows through a biological bath in a reaction vessel having a constant living mass. The dilution of the partial stream is regulated in such a manner through measurement of the oxygen content upstream and downstream of the reaction vessel, that with constant volume flow through the reaction vessel, the difference between the measurement values obtained remains essentially constant at a predetermined value, so that the amount of dilution serves for the indication of the level of pollution. Additional reaction vessels connected in parallel or in series with the first reaction vessel and having associated oxygen electrodes allows measurement of the toxicity and degradableness of the pollution.

Description

Claim 1: The solution to be tested is sampled in branches, aerated with oxygen, and continuously passed through a biological filter in which the amount of microorganisms in the filter bed is maintained at a substantially constant level in a reaction vessel. A pollution testing method for testing biologically degradable toxic components of a solution to be tested, such as wastewater, such as measuring the amount of
Dilute the branched flow with biologically neutral water, measure the amount of dissolved oxygen at the inlet of the reaction vessel, and compare it with the measurement result of the amount of residual oxygen. Biological analysis of a solution, characterized in that the dilution of the branched flow is controlled so that the difference between the measured values is constant with respect to a set value, and the dilution is used to express the degree of contamination. Method for testing degradable toxic components.

2. The concentration of the nutrient supplied to the reaction container and diluted is selected within a range where the reaction production rate of the living body and the nutrient supply amount are approximately linearly related. The method described in Section 1.

3. The concentration of the nutrients supplied and diluted to the reaction vessel is selected such that the reaction production rate of the living body does not exceed 1/2 of the maximum reaction production rate. or the method described in Section 2.

4. Nutrient supply measured by BOD ₅ , 1-15
4. The method according to claim 1, wherein the method is made constant between mg/mg/ml.

5. The method according to any one of claims 1 to 4 above, characterized in that a biologically neutral buffer solution is administered to the test solution to counter the inhibitory effect caused by fluctuations in PH value.

6. The method according to any one of claims 1 to 5 above, characterized in that the test liquid is flowed under a slightly pressurized state.

7. Collect the test solution as another second branch stream and process it in the same way as the first branch stream that was treated earlier, and at this time, the dilution of the second branch stream is a constant magnification (m). is adjusted to be smaller than that of the first branch flow, and the change in the difference between the measured values at the inlet and outlet of the second reaction vessel is compared with the change in the difference between the measured values in the first branch flow. 2. A method according to claim 1, characterized in that the degree of toxicity associated with the toxic components is displayed in comparison.

8. Method according to claim 7, characterized in that the multiplier (m) is chosen between 2 and 20 according to the type of toxicity expected.

9. The biological filter bed according to claims 1 to 8 above, characterized in that the biological filter bed is filled with a large number of free-floating objects having biological growth membranes, and is constantly moving in a turbulent manner. Method.

10 Pollution for testing biologically degradable toxic components of aqueous solutions such as wastewater, comprising an aeration tank and a reaction vessel through which branch streams of the aqueous solution are passed, and an oxygen electrode in the outlet conduit of the reaction vessel. As an apparatus for implementing the inspection method, a branch flow conduit 31 and a dilution water conduit 32 are connected to the inlet side of the aeration tank 3,
A flow rate control device 2 connected to a control device 12 is installed in a dilution water conduit 32, and an outlet 33 of an aeration tank 3 is installed.
In the conduit 60 connecting the inlet 71 of the reaction vessel 7,
Another oxygen electrode 1 connected to a control device 12
0, in which case the control device comprises a flow control device 2
Device for testing biologically degradable toxic components of a solution, characterized in that it has a comparator for and a control signal transmitter.

11. The apparatus according to claim 10, characterized in that metering pumps 1 and 2 are installed in the branch flow conduit 31 and the dilution water conduit 32, respectively.

12 The reaction vessel 7 is connected to a circulation pipe 8 through which the fluid in the reaction vessel 7 is continuously pumped by another pump 8.
12. Device according to claim 10 or 11, characterized in that it is connected to 1.

13 The biological filter bed held in the reaction vessel 7 contains a large number of free floating objects 9 having biological growth membranes.
13. A device according to claims 10 to 12, characterized in that it comprises:

14. Device according to claim 13, characterized in that the free-floating body 9 has a growth membrane that is protected from mechanical effects.

15. Device according to claim 13 or 14, characterized in that the free-floating body 9 is a hollow body with a free growing membrane on its inner surface.

16 The branch stream leaving the first reaction vessel from the previous treatment is routed through a second reaction vessel for subsequent treatment having a biological filter bed, and the oxygen consumption in the first reaction vessel and the second reaction vessel are 2. Process according to claim 1, characterized in that the difference in oxygen consumption in the reaction vessel is detected as a measure for the degradability of the pollution in the branched streams.

17 Diluting the branched stream that exited the first reaction vessel in the previous treatment and then allowing it to flow into the second reaction vessel to be treated next, and adjusting the degree of dilution of the branched stream flowing into the first reaction vessel, When the flow rate passing through the second reaction vessel is constant, the difference between the measured values at the inlet and outlet of the second reaction vessel is controlled to be approximately constant with respect to the set value. The degree of dilution in the reaction vessel is adjusted to be larger than that in the first reaction vessel by a constant magnification m, and the difference between the measured values before and after the second reaction vessel is the same as that measured in the first reaction vessel. 2. Method according to claim 1, characterized in that the difference in values is compared and expressed as the degree of toxicity associated with the toxic component.

18 Outflow pipe 7 of the first reaction vessel 7 in the previous treatment
2 is the inflow pipe 7 of the second reaction vessel 17 to be treated next.
1', another oxygen electrode 16 is installed after the second reaction vessel 17, and a conductor 4
11. Device according to claim 10, characterized in that it is connected to the control devices 12, 12 by means of 6'.

19 The outflow pipe 72 is connected to a tank 18 with an overflow 19, which is fitted with an outflow pipe 22 equipped with a metering pump 13, which connects its outlet with the inflow pipe 71' of the second reaction vessel 17; Further, a dilution water conduit 32' equipped with a metering pump 14 is connected to the inflow pipe 71', and oxygen electrodes are installed before and after the second reaction vessel 17, respectively. Claim 1 for carrying out the method according to claim 17
The device according to item 8.

20 A second aeration tank 3', a second reaction vessel 17, and another same apparatus b equipped with oxygen electrodes 15 and 16 installed before and after the second reaction vessel 17, respectively, are installed in parallel, and the second The flow rate control devices 13 and 14 installed in front of the aeration tank 3' are controlled by the control device 12 so as to change the dilution of the second branch flow from the dilution of the first branch flow by a constant magnification m. Claim 10
The equipment described in section.

Description: The present invention provides a method for collecting a solution to be tested, aerating it with oxygen, and continuously passing it through a biological filter in which the amount of microorganisms in the filter bed is maintained at a substantially constant level in a reaction vessel. The present invention relates to a method and apparatus for testing biologically degradable toxic components, such as measuring the amount of residual oxygen, for example, as the degree of pollution in an aqueous solution such as wastewater.

Determination of biochemical oxygen demand has traditionally been done with results usually available after 5 days (BOD ₅ ).
It has been carried out using the extraction test method. The conditions for this are stipulated in the "German Standard Test Method H4".
A continuous operating device for this purpose is not yet known.

Fish or microbial growth tests are generally used to determine the toxic components of aqueous solutions. The determination at this time is expressed as presence or absence. DE−OS25
No. 14609 discloses a method and apparatus for the determination of toxic components in aqueous solutions. However, even with this, it is not possible to distinguish between pollution and weakly toxic components, for example in wastewater. Therefore, this case is also expressed as presence or absence.

SUMMARY OF THE INVENTION An object of the present invention is to propose a method and apparatus for testing solution components that enable continuous measurement of biologically degradable contamination. For example, it must be possible to investigate the inhibition of microbial growth due to the presence of toxic components in aqueous solutions, especially wastewater or running water.

In order to solve this problem, the Michaelis-Menten model, which has been confirmed through many experiments, is
Used as a theoretical basis. Biological reaction products are expressed in terms of nutrient content by the following hyperbolic equation:

V=Vmax・L/Km+L (1) However, V: Reaction production rate Vmax: Maximum reaction production rate L: Amount of nutrients (or substrate, Nahvstoff) (substrate concentration) Km: Michaelis constant When the amount of nutrients is small, the Michaelis constant The formula is the first
Approximately expressed by a linear equation.

V=Vmax·L/Km (2) In practice, the meaning of equation (2) is as follows: When the substrate concentration is low, the reaction production rate is proportional to the concentration. That is, in this range, oxygen consumption increases linearly as the amount of nutrients increases. However, the prerequisite is that the amount of dissolved oxygen does not fall below 15% of its saturation value and therefore
tmacher reaktion (sequential reaction) does not occur.

Strictly speaking, the Michaelis equation holds true only when the substrate concentration changes, the amount of oxygen remains constant, and the diffusion of nutrients to oxygen is unhindered. These conditions, as shown in previous studies,
This is achieved by allowing the suspended flowing hollow body as a growth film of the microorganisms to flow at a constant high circulation rate within the reaction vessel, so that the growth rate of the microorganisms and the cleaning rate are equal.

Based on the above, the solution to this problem in the present invention is to dilute the branched stream (Teilstrom) with biologically neutral water, and the dilution degree of this branched stream is determined by the amount of dissolved oxygen at the inlet of the reaction vessel. When the flow rate passing through the reaction vessel is constant, the difference in the measured value is controlled to be approximately constant with respect to the set value, and in this case, This is a modification of the method known from DE-OS 25 14609 mentioned above, characterized in that the degree of dilution is used to express the degree of turbidity in relation to the solution components.

The amount of dissolved oxygen in the branched flow from the liquid to be tested is:
It is measured at the inlet and outlet of the reaction vessel that has a growth film of microorganisms inside. The difference in oxygen content is maintained at a constant value with only a small fluctuation range. This ensures that the substrate supply and the microorganism oxygen consumption in the reaction vessel remain constant. If the growth surface in the container is constant, the amount of microorganisms will also be constant due to constant scrubbing and cleaning. Particularly suitable are floating, flowing hollow bodies that form a growth film that is protected against friction.

In an embodiment of the present invention, the concentration Lk (see FIG. 3) supplied to the reaction vessel is selected within a range where the reaction production rate of the living organism and the amount of nutrients supplied are approximately linearly related. This is generally expected to hold true when the reaction production rate is 1/2 or less of the maximum reaction production rate (Vk<Vmax/2). In this range, we can expect a very natural reaction of the living body to the concentration fluctuation, and it is also possible to base it on a linear relationship.

If pH fluctuations in the liquid to be tested are expected, inhibitory effects on microorganisms can be avoided by appropriate administration of biologically neutral buffers.

By slightly pressurizing the device, oxygen solubility can be increased and cavitation in parts of the device can be avoided.

When the activity of microorganisms in the reaction vessel is kept constant as in the present invention, the dilution rate and the measured
From the difference in the amount of O ₂ and the temperature, the degree of pollution associated with the biologically degradable toxic components of the test liquid can be determined. This can also be directly expressed as a BOD ₅ value through comparative measurements and equipment validation. The scope of application of this BOD measurement method is, for example, the recording of biologically degradable pollution loads in purification plants and the control of such plants according to the actual oxygen demand.

When a toxic substance is present in the test liquid, the growth of microorganisms is inhibited depending on the concentration of the toxic substance.

To carry out the method according to the invention and test the toxic components of the solution, the test solution is taken as another branch stream and treated in the same way. At this time, the degree of dilution of the second branch flow is adjusted to be smaller than that of the first branch flow by a certain magnification (m),
The difference in measurements at the inlet and outlet of the second reaction vessel is compared to the difference in measurements in the first branch stream to indicate the degree of toxicity associated with the toxic component.

In the first reaction vessel, the dilution level is controlled by the method described above, and in the second vessel, a magnification of "1/m" is always set so that the concentration of the toxic substance is always m times that of the first vessel.
When operating two reaction vessels in parallel so that a branch flow with a lower dilution level flows in, the first
When the dilution level of the toxic substance is adjusted to such an extent that it does not cause an inhibitory effect in the second reaction vessel, the presence or absence of toxicity and its degree can be estimated from the decrease in the amount of oxygen consumed in the second reaction vessel.

In the toxicity measurement method according to the present invention, BOD measurement is carried out in parallel with two different dilutions.
As the concentration increases, the inhibitory effect of the toxic substance becomes more proportional, so its toxicity was measured in both branch streams a and b with reference to the dilution of the first container. Activity ratio BODa/
Expressed in BODb.

The scope of application of the present invention is an alarm mechanism built into a biological treatment section of a water purification system installed in front of a drain outlet for wastewater containing toxic components.

In another method according to the present invention, in order to determine the toxic components of an aqueous solution in absolute values, a "standard organism" is first cultured and maintained in a reaction vessel containing a substrate of known composition without introducing toxic components. I'll keep it.
Thereafter, the aqueous solution containing the toxic component is introduced into a "standard organism" and the activity of the microorganism is recorded, with the so-called 0 point being defined as the time when there is no inhibition of the respiratory ability based on the preliminary measurements. By testing and measuring intermittently in this manner, the absolute value of the toxic component can be determined based on the "standard organism."

The invention furthermore relates to a device for testing solution components for the determination of biologically degradable pollution in aqueous solutions, in particular wastewater and running water, and for the determination of the inhibitory effect of toxic substances on microorganisms.

An apparatus for carrying out the method of the invention, comprising an aeration tank and a reaction vessel through which a branch stream from an aqueous solution is passed, and an oxygen electrode in the outlet conduit of the reaction vessel, comprises a branch on the inlet side of the aeration tank. A flow conduit and a dilution water conduit are connected, a flow control device connected to a control device is installed in the dilution water conduit, and a flow rate control device connected to a control device is installed in a conduit connecting an aeration tank outlet and a reaction vessel inlet. A further oxygen electrode is connected, the control device being characterized in that it has a comparator for the flow control device and a control signal transmitter. Flow rate control can be implemented by installing metering pumps in each of the branch flow conduit and the dilution water conduit, depending on the purpose.

The growth film within the reaction vessel is made up of free-floating objects with the growth film protected against friction. The mass and the contents of the reaction vessel are constantly mixed, depending on the purpose, by a stirring device or a circulation device. At the front of the conduit of the aeration tank, it is possible to optionally pass a strainer and a stirrer in order to further homogenize the test liquid.

The measured value of O ₂ ensures that the difference in O ₂ is a constant value when the flow rate through the reaction vessel is constant;
A computer is used to control the flow rate ratio of the test liquid and dilution water so that the flow rate does not drop below the lower limit at the outlet.
This control value is shown as an index.

A similar second reaction vessel, connected in parallel with the first reaction vessel and equipped with one oxygen electrode before and after it, is used for measuring the degree of pollution related to the toxic components of the branched streams or Used for detection.

In order to detect toxic components by arranging BOD measuring devices in series, in an embodiment of the method according to the invention the test liquid is treated twice in the same way.
At that time, the dilution level in the second reaction vessel is adjusted to be smaller than that in the first reaction vessel by a certain magnification (m), and the difference between the measured values before and after the second reaction vessel is It is compared with the measured value of reaction vessel 1 and displayed as the degree of contamination related to the toxic component or the degree of content of the toxic component.

In the first reaction vessel, the degree of dilution is controlled in the manner described above, but by means of the oxygen electrode in the vessel 17 placed downstream, and in the second vessel, the toxic substance is 1/m times that of the first vessel. In order to maintain the same concentration, a branch flow with a higher dilution by the magnification "m" always flows in.
When operating two reaction vessels in series, when adjusting the dilution level to such an extent that the toxic substance does not cause an inhibitory effect in the rear reaction vessel, the presence or absence of toxic components can be determined from the decrease in oxygen consumption in the first reaction vessel. and its extent can be estimated.

In the method for detecting toxic components in the present invention, BOD measurements before and after changing the dilution level are problematic. The inhibitory effect of toxic substances increases more than proportionally as the concentration increases;
The degree of toxicity as the degree of toxicity related to the toxic component is expressed as the ratio of the activities measured in both reaction vessels (ratio of BOD) based on the degree of dilution in the reaction vessel.

When microorganisms are damaged over a long period of time by strong toxic effects, it is possible to remove the floating mass with propagation from the reaction vessel and replace it with a new one with non-toxic flocs. be.

Next, the present invention will be explained using the accompanying drawings.

Fig. 1 is a BOD measurement equipment shown as an embodiment of the present invention, Fig. 2 is an equipment for simultaneous measurement of BOD and toxicity, Fig. 3 is a reaction diagram, and Fig. 4 is an example of another embodiment of the present invention. Diagrammatic Illustration and FIG. 5 is a diagrammatic illustration of yet another embodiment of the invention.

As shown in Figure 1, the investigation fluid is metering pump 1
and the dilution water is added to the mixture through an aeration tank 3 where a solution for PH-buffering is added through conduit 4.
is supplied by a metering pump 2 on the suction side. By supplying air or gaseous oxygen through the conduit 5, the fluid in the aeration tank 3 is enriched with oxygen. The flow of fluid discharged from the aeration tank 3 through the outflow pipe 33 is transferred to the conduit 71 at a constant flow rate by the pump 6.
It is guided to the reaction vessel 7 via. A first oxygen electrode 10 is inserted into the conduit 60 connecting the pump 6 and the inflow pipe 71 to measure the oxygen concentration and temperature of the flowing fluid and send the measured values to the control computer 12. be done.

Fluid flow entering the reaction vessel 7 coupled to its outside via conduit 71 is connected to a drain 72 attached to the opposite end of the reaction vessel 7 and to which another oxygen electrode 11 is attached. through which it flows out of the reaction vessel 7. Oxygen electrode 11 measures the temperature of the effluent stream and the oxygen temperature and sends the measured values in the form of a signal to computer 12. The drain pipe 72 is the oxygen electrode 11
Pour into a drainage container not shown on the outflow side.

The reaction vessel 7 is connected to circulation lines 81, 82 through which the fluid present in the reaction vessel 7 is continuously circulated by a circulation pump. A circulation line 82 connected to the outlet side of the circulation pump 8 flows into the bottom of the reaction vessel 7, and a circulation line 81 receiving fluid from the reaction vessel 7 connects to a number of branch lines 8.
3 and 84 to the ceiling of the reaction vessel 7.

The reaction vessel contains a large number of floating bodies with growth films for microorganisms that are constantly in motion due to the fluid circulating within the reaction vessel 7. tube 8
Filters 9a, 9b, and 9c with meshes smaller than that of the suspended solids 9 are installed in front of the openings of the reaction vessel 7 into which the suspended solids 3, 84, and 72 flow. Although not shown, in addition to the circulations 81 and 82, a stirring mechanism is previously provided in the reaction vessel 7, which is driven by the inflow from the conduit 71 or separately from the outside.

The control device uses the BOD calculated by the computer 12.
A control cable 40 from the calculator 12 containing an indicator controlled by the calculator 12 for displaying or printing out values to the metering pump 1 in the inlet pipe 31 for the aeration tank 3 and the inlet pipe 32 for the dilution water. A control cable 42 to the metering pump 2 inside is coming out. First oxygen electrode 10
Control cables 44, 46 between the second oxygen electrode 11 and the computer 12 send the measured values measured by the oxygen electrodes to the computer 12.

In FIG. 2, the installation according to FIG. 1 is once again shown diagrammatically in the upper half, and in the lower half another similar installation for the detection of toxic components is diagrammatically illustrated. This further installation basically consists of the same equipment and components as the above-mentioned installation, so that on the inlet side of the aeration tank 3' there is a conduit 3 for supplying the pollutant solution.
1' is attached. A metering pump 13 is also installed in the conduit 31'. On the upstream side, conduit 31' is connected to the upstream side of conduit 31, so that the two conduits 31 and 31' are connected with the contaminated investigation solution in a container not shown.
A metering pump 1 is installed on the inflow side of the other aeration tank 3'.
4 as well as an inlet pipe 32' for dilution water. In the drain pipe 60' from the aeration tank 3', there is a system that transmits the concentration and temperature of the fluid flow to the computer 12 by means of a control cable 44' via a computer 12' that takes the difference between the measured values of the electrodes. An oxygen electrode 15 is further attached. The oxygen electrode 15 is connected to the reaction vessel 7
It is connected via an inlet pipe 71' to the reaction vessel 17, which is the same as and also connected to a circulation line 81'. In the drain pipe 72' from the reaction vessel 17 there is another oxygen electrode 16 which conducts the measured oxygen concentration and temperature of the waste water to the computer 12 via the computer 12' and through the control cable 46'. A control cable 48 from the computer 12 is connected to the metering pump 13 for inflowing polluted water, and a control cable 49 is connected to the metering pump 1 for dilution water.
It is connected to 4. The calculator 12 controls the metering pumps 13, 14 through control cables 48, 49 so that the unpurified fluid concentration of the fluid supplied to the aeration tank 3' is always m times the corresponding concentration of the fluid supplied to the aeration tank 3. move. By comparing the measurements of the oxygen electrodes 15 and 16 with the measurements obtained with the oxygen electrodes 10 and 11, it is possible to prevent inhibition of toxin components that may occur against microorganisms.

The installation according to FIG. 2 can also be used as a detector of toxic components by intermittent measurements using reference organisms. During measurement interruptions, both devices are used with standardized (nutrient) substrate solutions for culture and regeneration of reference organisms.

In Figure 3, the horizontal axis shows the substrate concentration, the upper part of the vertical axis shows the reaction rate, and the lower part shows the dilution ratio of 1:n.With a constant minute substrate concentration "Lk", organic matter is always kept in an idealized linear region. act.

V=Vmax·L/Kmn+1=L/Lk When the substrate concentration L is large, n and L are always proportional to each other in the range where _V1 and _V2 and the measurement error to be considered are difficult to clearly distinguish.

In the case of the installation according to FIG. 4, the outlet pipe 72 of the return stream a is connected to the second oxygen electrode 15 and via the inlet pipe 71' to the second reaction vessel 17 and also to the control cable 44. A transport pipe 73 which is connected to a control computing unit 12' is connected via '. The oxygen electrode 16 inserted into the delivery pipe 72' of the reaction vessel 17 is connected to the control cable 4.
It is connected to the arithmetic unit 12' via 6'. The series connection of the two reaction vessels 7 and 17 makes it possible, in addition to the BOD measurement, also to measure the degree of pollution associated with toxic components in the return stream a. BOD values of a certain magnitude can result from better or worse degradable materials. Until now, people have considered this situation to be BOD ₅ value and COD
This has been taken into account by examining the relationship with (chemical oxygen requirement). In a viable method using the installation according to FIG. 4, the microorganisms in the first reaction vessel are supplied with a certain contamination in the return stream a. This pollution is decomposed to a residual amount in the first reaction vessel depending on the composition of the pollution. Depending on its amount, this residual contamination in the return flow passing through the transport tube 73 causes various differences in the amount of oxygen between the oxygen electrodes 15 and 16 when flowing through the second reaction vessel 17. The difference in the various amounts of oxygen indicates the evaluation criterion for the decomposability of the contaminant contained in the return flow a.

The installation according to FIG.
If connected to two connected tanks 18, it can also be used to measure the degree of toxicity associated with the toxic components of the liquid stream. Outflow pipe 22 passes through metering pump 13 to oxygen electrode 15 and from there to second reaction vessel 17 via inflow pipe 71'. An overflow pipe 19 is attached to the tank 18. The outflow side of the metering pump 14 for dilution water from the conduit 32' is opened in the middle of the pipe between the metering pump 13 and the oxygen electrode 15, and at this time, fluid flows back into the conduit through the metering pumps 13 and 14. A mechanism is provided in advance to prevent this. If necessary, an aeration tank (not shown) must also be connected to the middle of the conduit 23. In that case, the control device is set such that metering pumps 1 and 2 are controlled by signals from oxygen electrodes 15 and 16. The metering pump 13 is controlled through the cable 48 to draw a fixed percentage less fluid from the tank 18 than the metering pump 1 supplies. The metering pump 14 is controlled via a cable 49 to ensure the required volumetric constant of flow through the reaction vessel 17 by adding a substantial amount of dilution water. The amount of fluid discharged through the overflow pipe 19 of the tank 18 must be regulated through the pump 14 depending on the conditions mentioned above.

If the return stream a flowing through the conduit 73 is diluted in proportions, the second reaction vessel 17
The toxicity of the return stream flowing into the second reaction vessel 17 through the inlet tube 71' decreases as a function of dilution, since the microbial activity therein is not inhibited at all or only to a small extent. As a result, the oxygen electrode 15
The difference between the measured values measured by the oxygen electrode 10 and 16 is
This means that it is different from the difference in concentration measured by and 11. This difference in difference gives the calculator a certain toxic content in the selected material in return stream a. Pumps 13 and 14 mix the fluid flows such that the concentration in reaction vessel 17 is proportionally lower than in reaction vessel 7. The volumetric flow rates in both containers must then be constant and can be equal.

The invention is of course not limited to the embodiments described above. In addition, in the case of equipment according to Figure 4,
Oxygen electrode 15 can be omitted, in which case the difference between the measured oxygen values of electrodes 11 and 16 is processed by computer 12. Further, an aeration tank is further connected in series to the reaction vessel 17 as required.

Preliminary measurement reaction time: 5 minutes Volume flow rate: 1/min Therefore, at 20° C. and 760 Torr, it is defined as 9 mgO ² /min, that is, 9 mgO ₂ /min. If the operating pressure is higher, the prescribed oxygen is Henry's law Cs
= Calculated by Ks・Pt.

The minimum amount of oxygen at the electrode 11 is defined as 2 mgO ² /. Therefore, the oxygen consumption capacity is up to 7
mg/.

According to preliminary experiments, a certain quality concentration Lk,
a (equivalent to 5 mg BOD ₅ /), the required amount of oxygen is 2.5 gO ² /m ² ·day = 1.7 mgO ₂ /m ² ·min,
In the case of Lk, b (equivalent to 25 BOD ₅ /), the oxygen requirement is 5gO ² /m ² ·day = 3.4mgO ² /m ² ·min.

Under this assumption, the 7 mg/min oxygen supply is consumed through the 4.1 and 2.05 m ² of growth film grown on the surface of the float 9.

The following floating objects are selected: When packed loosely, the surface area ratio is 2.1 m ² /
A hollow cylinder with an inner diameter of 3 mm and a height of 3 mm, which is
37037 pieces/.

According to the measurements, reaction vessel 7 was filled with 72,310 hollow cylinders (4.1 m ² ) and reaction vessel 17 was filled with 36,155 hollow cylinders (2.05 m ² ).

The hollow cylinder, when packed most loosely, has a reaction volume of
Requires 39 and 19.5%. Therefore, the cylinder can move sufficiently.

According to preliminary measurements, Lk, a was 5 mg BOD ₅ / and
Lk and b are determined to be 25mgBOD ₅ /.

When the mixing ratio is 1:n, the total substrate concentration L-
The quantity measured as BOD ₅ /- is calculated as follows.

BODa=Lk, a・(n+1)=L(mgBOD ₅ /) BODb=Lk, b・(n+1)/m・ΔO ₂ b
/ΔO ₂ b, T (mgBOD ₅ /) The calculator does not treat the value of Lk as a constant, but instead calculates 10
Each time the calculated value ΔO ₂ between and 11 changes by 0.1 mgO ₂ /, the values of Lk, a and Lk, b can be increased or decreased by 1.4%.

Meaning of the symbols in the formula: L = Substrate concentration BOD = Biochemical oxygen requirement BOD ₅ = Biochemical oxygen requirement for 5 days Lk = Constant substrate concentration a, b measured as BOD ₅ (mg/) = subscript ΔO ₂ for the reaction processes in vessels 7 and 17 = calibration value ΔO ₂ b, T = adjusted by changes in the growth film based on the expected wastewater fluctuations (inflow or outflow of the water purification plant) Control value m compared with calibration value ΔO ₂ b = correction factor n for substrate concentration in container 17 = proportion of dilution water L(t) = substrate concentration at time “t” Function of the measuring equipment according to the calculation example The explanation begins with an explanation of the steady analysis state (dilution ratio, waste water/dilution water 1:n ₁ ).

A certain amount of substrate Lk, a is added to the organic matter in the reaction vessel 7.
(for example, 5 mg BOD ₅ /) is derived. The mixing ratio is 1:n ₁ , BODa=Lk, a·(n ₁ +1)=L.
The difference in oxygen content between electrodes 10 and 11 is ΔO ₂ a (7 in the example)
mgO ₂ /).

When the pollution concentration L increases, organic matter reacts with higher respiratory activity. Therefore, electrode 1
0 and 11 record a larger difference in oxygen content.
When ΔO ₂ a = 7.1 mgO ₂ /, the pumps are 10 and 11
The wastewater rate (pump 1) is controlled to be decreased and the dilution water rate (pump 2) to be increased until the O ₂ difference between is readjusted to 7 mgO ₂ /.

Therefore, the new mixing ratio is 1:n ₂ , and
BODa=Lk, a・(n ₂ +1)=L.

If the pollution concentration L is decreased, the process moves in the opposite direction.

In the case of parallel operation of two reaction vessels, pumps 1 and 1 are used when measuring BOD and monitoring toxic components at the same time.
3 and 2, 14 are controlled through electrodes 10 and 11 in the manner described above. Pump 13 supplies m times as much as pump 1.

Electrodes 15 and 16 monitor only the oxygen consumption within reaction vessel 17. Corresponding to the O ₂ difference ΔO ₂ b, T, there is no suppression in the preliminary measured value ΔO ₂ b (7 mgO ₂ /in the example). In this case BODa and BODb are equal.

If there are toxic effects, the ratio BODa/BODb
The degree of consumption suppression that exists can be known in relation to the dilution ratio of 1:n.

As detailed in the above embodiments, the present invention involves branching and sampling a solution to be tested, aerating it with oxygen, and continuously forming a biological filter bed in which the amount of microorganisms in the filter bed is maintained at a substantially constant level in a reaction vessel. The degree of pollution associated with biologically degradable toxic components of aqueous solutions such as wastewater, such as measuring the amount of residual oxygen after passing through a
Regarding the method and apparatus for measuring degradability or toxicity, the branched stream is diluted with biologically neutral water and the amount of dissolved oxygen is measured at the inlet of the reaction vessel;
Compared with the measurement result of the amount of residual oxygen, when the flow rate passing through the reaction vessel is constant, the dilution of the branched flow is controlled so that the difference in the measured value is approximately constant with respect to the set value, In this case, dilution is used to express the degree of contamination of the polluted solution, while two reaction vessels equipped with oxygen electrodes are connected in parallel or in series to express the dilution of the branched flow flowing through the second reaction vessel. ,
A constant magnification with respect to the dilution of the first branch flow,
By knowing the changes in the oxygen consumption in the first and second reaction vessels, it is possible to detect the toxic components of the pollutants, and also to direct the branched flow from the first reaction vessel to the second reaction vessel. When leading to the reaction vessel,
The difference in the amount of oxygen consumed in both reaction vessels makes it possible to indicate the so-called degradability of pollution or the degree of toxicity related to toxic components.

Below, various embodiments of the method and apparatus for testing degradable toxic components in solutions according to the invention will be illustrated.

1 Dilute the branched flow with biologically neutral water, measure the amount of dissolved oxygen at the inlet of the reaction vessel, and compare it with the measurement result of the amount of residual oxygen.When the flow rate passing through the reaction vessel is constant, The dilution level of the branched flow is controlled so that the difference between the measured values is approximately constant with respect to the set value, and the dilution level is used to represent the turbidity of the polluted solution.
The solution to be tested is collected in branches and aerated with oxygen,
Biological decomposition of an aqueous solution such as wastewater, for example, by measuring the amount of residual oxygen after passing it continuously through a biological filter in which the amount of microorganisms in the filter bed is maintained at a nearly constant level in a reaction vessel. Possible ingredient testing methods.

2. The method according to item 1 above, wherein the concentration of the nutrient supplied to the reaction container and diluted is selected within a range where the reaction production rate of the living body and the nutrient supply amount are approximately linearly related. the method of.

3. The above item 1 or 2, wherein the concentration of the nutrient supplied and diluted to the reaction container is selected so that the reaction production rate of the living body does not exceed 1/2 of the maximum reaction production rate. The method described in.

4. Nutrient supply measured by BOD ₅ , 1-15
The method according to the above item, characterized in that the amount is constant between mg/.

5. The method described in the above item, characterized in that a biologically neutral buffer solution is administered to the test solution against the inhibitory effect caused by fluctuations in PH value.

6. The method described in the above item, which is characterized by flowing under a slightly pressurized state.

7. Collect the test solution as another branch stream and process it in the same way, adjusting the dilution of the second branch stream to be smaller than that of the first branch stream by a certain factor (m). The degree of toxicity associated with the toxic component is indicated by comparing the change in the difference between the measurements at the inlet and outlet of the second reaction vessel with the change in the difference in the measurements at the first branch stream. The method described in the above item, characterized in that:

8. Method according to item 7 above, characterized in that the multiplier (m) is chosen between 2 and 20 according to the type of toxicity expected.

9. The method described in the above item, wherein the biological filter bed is filled with a large number of free floating objects having biological growth membranes, and is constantly moving in a turbulent manner.

10 A branch flow conduit 31 and a dilution water conduit 32 are connected to the inlet side of the aeration tank 3, and a flow rate control device 2 connected to the control device 12 is installed in the dilution water conduit 32, Another oxygen electrode 10 connected to the control device 12 is provided in a conduit 60 connecting the inlet 71 of the reaction vessel 7 and the oxygen electrode 12.
In this case, the control device comprises an aeration tank and a reaction vessel through which the branched flow of the aqueous solution passes, characterized in that it has a comparator and a control signal transmitter for the flow rate control device 2, and an outlet conduit of the reaction vessel. An apparatus for carrying out the method described in the above item, comprising an oxygen electrode therein.

11. The device according to item 10 above, characterized in that metering pumps 1 and 2 are installed in the branch flow conduit 31 and the dilution water conduit 32, respectively.

12 The reaction vessel 7 is connected to a circulation pipe 8 through which the fluid in the reaction vessel 7 is continuously pumped by another pump 8.
1.
Apparatus according to paragraph 10 or paragraph 11.

13. The tenth aspect of the above, characterized in that the biological filter bed held in the reaction vessel 7 contains many free-floating objects 9 having biological growth membranes.
Apparatus according to paragraphs 12 to 12.

14 The free-floating object 9 is characterized in that it has a growth membrane protected from mechanical action.
The device described in paragraph 13.

15. The device according to item 13 or 14 above, characterized in that the free-floating object 9 is a hollow object having a free growth membrane on its inner surface.

16 The branched stream leaving the reaction vessel 7 is sent through a second reaction vessel 17 having a biological filter bed so that the difference between the oxygen consumption in the first reaction vessel and the oxygen consumption in the second reaction vessel is , is detected as a measure for the degradability of contamination in the branched flow.

17 The branched stream leaving the reaction vessel is diluted before flowing into the second reaction vessel, and the degree of dilution of the branched stream entering the first reaction vessel is controlled such that the flow rate passing through the second reaction vessel is constant. In this case, the difference between the measured values at the inlet and outlet of the second reaction vessel is controlled to be approximately constant with respect to the set value, and in this case, the degree of dilution in the second reaction vessel is controlled to be equal to that of the first reaction vessel. The difference between the measured values before and after the second reaction vessel is
Items 1 to 6 or 9 above, characterized in that the difference in the measured value in the first reaction vessel is compared and displayed as the degree of toxicity related to the toxic component.
The method described in section.

18 The outflow pipe 72 of the first reaction vessel 7 is connected to the inflow pipe 71' of the second reaction vessel 17, and another oxygen electrode 1 is connected after the second reaction vessel 17.
10 to 15, for carrying out the method according to paragraph 16, characterized in that 6 is attached to the control device 12, 12 by a conductor 46'. .

19 The outflow pipe 72 is connected to a tank 18 with an overflow 19, which is fitted with an outflow pipe 22 equipped with a metering pump 13 whose outlet is connected to the inflow pipe 71' of the second reaction vessel 17; Further, according to the above item 17, the dilution water conduit 32' equipped with the metering pump 14 is connected to the inflow pipe 71', and oxygen electrodes are installed before and after the second reaction vessel 17, respectively. 19. Apparatus according to paragraph 18 above for carrying out the method described.

20 This device is installed in parallel with another same device b, which is equipped with a second aeration tank 3', a second reaction vessel 17, and oxygen electrodes 15 and 16 installed before and after the second reaction vessel 17, respectively. The flow rate control devices 13 and 14 placed in front of the second aeration tank 3' are
The control device 1 controls the dilution level of the second branched stream to be different from the dilution level of the first branched stream by a constant magnification m.
2.
Apparatus according to items 10 to 15 above, for carrying out the method according to items 7 to 9 above.